Slicing machine having a knife monitoring device

Abstract

An electrically operated slicing machine cuts off slices from an item. The slicing machine has: a cutting device, the cutting device having a rotating circular knife driven by an electric knife motor; a carriage, movable in parallel to the circular knife, for receiving and moving the item to be cut; and a knife monitor for monitoring a state of the circular knife. The knife monitor has a current-measuring device for measuring a knife motor current. The slicing machine has a control unit which is configured to determine a cutting characteristic value from the currently measured knife motor current and/or its temporal profile.

1 . An electrically operated slicing machine for cutting off slices from an item, the slicing machine comprising:
 a cutting device, wherein the cutting device comprises a rotating circular knife driven by an electric knife motor;   a carriage, movable in parallel to the circular knife, for receiving and moving the item to be cut; and   a knife monitor for monitoring a state of the circular knife,   wherein   the knife monitor has a current-measuring device for measuring a knife motor current, and   wherein the slicing machine has a control unit which is configured to determine a cutting characteristic value from the currently measured knife motor current and/or its temporal profile.   
     
     
         2 . The slicing machine according to  claim 1 ,
 wherein the slicing machine comprises a non-volatile data memory, and   wherein the control unit is configured to store in the non-volatile data memory the currently measured knife motor current and the temporal profile or intermediate results derived therefrom, in particular an integral value of a net current of the knife motor starting from a completion of a previously run knife grinding program.   
     
     
         3 . The slicing machine according to  claim 1 , wherein the slicing machine has a grinding monitor for monitoring a grinding process using a knife grinding device. 
     
     
         4 . The slicing machine according to  claim 1 , wherein the slicing machine has a signal output unit that is configured to indicate a necessity of initiating a knife grinding process visually and/or acoustically. 
     
     
         5 . A method for monitoring an electrically operated slicing machine for cutting off slices from an item to be cut, the slicing machine comprising: a cutting device, the cutting device comprising a rotating circular knife driven by an electric knife motor; a carriage, movable in parallel to the circular knife, for receiving and moving the item to be cut; and a knife monitor for monitoring a state of the circular knife, the method comprising:
 sensing a knife motor current and/or its temporal profile as measurement data for input into the knife monitor; and   determining a current cutting characteristic value from these measurement data.   
     
     
         6 . The method according to  claim 5 , wherein a load-dependent current component and/or a load-independent current component of the knife motor current are determined as the measurement data. 
     
     
         7 . The method according to  claim 6 , wherein the cutting characteristic value is a soiling characteristic value and/or a wear characteristic value and/or a knife sharpness characteristic value, and
 wherein the soiling characteristic value and/or the wear characteristic value is derived from the load-independent current component and/or the knife sharpness characteristic value is derived from the load-dependent current component.   
     
     
         8 . The method according to  claim 6 , wherein the current load-independent current component is determined at predefined time intervals as a result of predefined events and/or after reaching a predefined cutting power limit. 
     
     
         9 . The method according to  claim 8 , wherein at the beginning of each start-up of the slicing machine, a no-load current of the knife motor is first measured and the current load-independent current component is determined therewith. 
     
     
         10 . The method according to  claim 5 , wherein the measurement data or the intermediate results determined from the measurement data are temporarily stored in a non-volatile data memory. 
     
     
         11 . The method according to  claim 5 , wherein an integral value, in particular starting from the completion of a previously run knife grinding program, is determined as an intermediate result. 
     
     
         12 . The method according to  claim 5 , wherein a target/actual comparison to a predefined limit value and/or to a dynamically determined limit value takes place with a measurement datum and/or with an intermediate result. 
     
     
         13 . The method according to  claim 12 , wherein an indication signal is output via a signal output unit when a value of the cutting characteristic value reaches and/or exceeds or falls below the predefined limit value and/or the dynamically determined limit value. 
     
     
         14 . The method according to  claim 12 , wherein a knife grinding program for sharpening the circular knife is started when the value of the cutting characteristic value reaches and/or exceeds or falls below the predefined limit value and/or the dynamically determined limit value. 
     
     
         15 . The method according to  claim 5 , wherein by based on the knife motor current and/or the temporal profile, an operation of the slicing machine during the knife grinding program is detected, and/or controlled. 
     
     
         16 . The method according to  claim 5 , wherein on the basis of the knife motor current and/or the temporal profile, a deburring process of the circular knife is detected, monitored, controlled, and/or a deburring indication signal which indicates an outstanding and/or a completed deburring process is output on the signal output unit. 
     
     
         17 . The method according to  claim 14 , wherein the dynamically determined limit value is determined at the start of the knife grinding program from the current cutting characteristic value. 
     
     
         18 . The method according to  claim 14 , wherein the knife motor is operated at a predetermined grinding speed at the start of the knife grinding program. 
     
     
         19 . The method according to  claim 18 , wherein the knife motor is operated in a first step at a predetermined sensing speed at the start of the knife grinding program, and the knife motor is determined, and the characteristic of the circular knife is determined from the knife motor current measured in the first step,
 wherein in a second step, the knife motor is operated at a predetermined grinding speed, wherein the predetermined grinding speed depends on the characteristic determined in the first step, and   wherein the circular knife is ground in the second step.   
     
     
         20 . The slicing machine according to  claim 1 , wherein the cutting characteristic value is a soiling characteristic value and/or a wear characteristic value and/or a knife sharpness characteristic value.